1. Field of the Invention
The present invention relates generally to a novel boosted power supply for an internal, on-chip regulator circuit which includes a differential amplifier coupled to a series regulating element operating as a source follower. In greater detail, pursuant to the teachings of the subject invention, a voltage pump circuit is provided to generate a boosted power supply for the differential amplifier.
2. Discussion of the Prior Art
As CMOS technologies scale down with consequential gate length reduction, the power supply voltages need to be lowered to prevent problems associated with breakdown, punch-through, and/or hot-carrier related problems. However, the external power supply voltages cannot be reduced easily because the system power supplies tend to remain at standard levels, e.g., 5 V or 3.3/3.6 V (in the foreseeable future). One way to satisfy these requirements is to use on-chip voltage regulators with a dropout voltage equal to the difference between the system power supply and a scaled internal power supply. Typical CMOS on-chip regulator circuits consist of a differential amplifier and a series regulating element operating in a source-follower mode. However, these circuits are not suited for small dropout applications such as 3.3/3.6 to 2.5 V conversion, and also have problems with poor power supply rejection.